Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Quantum myth 3: nature is fundamentally random

  1. Apr 29, 2008 #1
    We are discussing the Demystifier's paper "Quantum mechanics: myths and facts". http://xxx.lanl.gov/abs/quant-ph/0609163

    Myth 1 https://www.physicsforums.com/showthread.php?t=229497
    Myth 2 https://www.physicsforums.com/showthread.php?t=230693

    QM implies that nature is fundamentally random

    The topic is the claim that the common statement that nature is fundamentally random--as opposed to merely unpredictable--is a myth. By myths we mean widely repeated statements which, true or false, are not something we can validly assert given our current understanding.

    I don't have any questions about this section of the paper myself and have included it only for completeness sake. I'm ready to discuss any aspect anyone else wants to discuss.

    However, I will add that I have a severe case of gut reaction against objective randomness. Consider an event which has possible outcomes A and B. The event occurs and we observe B instead of A. The claim that "the outcome of this event is random" can only mean that if we ask, "Why did B occur and not A?" the answer must be "no reason; none." To say "B happened because .." is to identify that which determined B and that is to say it was not random. But this is to say, once again, that there is no reason that B occurred. Things just happen for no reason?!?! And somehow this multitude of things happening for no reason conspires to create the visible macro order? I can't accept that.

    And to say "there is no reason B occurred," whether true or not, bugs me because it is a willful decision to stop looking. It is too much like the creationist who says that evolution can't explain all the facts so we should just accept that God did it. To attribute something to miracle or to it-just-happens, either one, is to just give up. Benjamin Franklin could just as well have shrugged his shoulders and said, "Who knows about lightning? It just happens."

    (I don't have anything against miracles per se. I'm a theist. But scientists qua scientist should not incorporate them into the scientific approach since it necessarily puts an end to the method.)

    We say of a supposed random event, "It could turn out A or B". Afterwards, we say that although B happened, it could have been A. What do we mean by "could have been"? B happened, period. I haven't thought it about long enough, and haven't read enough, but I suspect that the notion of "could have been otherwise" would turn out to have serious logical problems on close examination.

    Just a hunch.
  2. jcsd
  3. Apr 29, 2008 #2
    I think a better definition of random is that under identical starting conditions, any two tries are not guaranteed to have the same result. This definition naturally excludes pseudorandomness or chaotic systems, as it is a fact that in such systems, though minute changes in starting conditions have drastic effects over time, identical starting conditions still yield identical results.

    The problem, of course, is that thorugh this definition nothing can be proven to be ranodm because starting conditions can never be identical. To paraphrase Bell, the moons of jupiter will be in different positions. So it is always possible that everything we observe now is inevitable based solely on the starting conditions at the time of the Big Bang, and that could the Big Bang be replicated in perfect detail, everything would transpire as it has here.

    A philosophical argument in support of fundamental randomness is related to free will, obviously. Because if QM were not fundamentally random, that means that while thought processes may be chaotic and thus appear random, they are still fundamentally deterministic, and there is, thus, no such thing as "true" free will. We make our decisions based solely on where the electrons in our brains were preordained to go 12 billion years ago. This is not a comforting thought.
  4. Apr 29, 2008 #3
    I always found the implications to free will that follow from the idea that my thoughts are random as being more disturbing than if they are deterministic. ;-)
  5. Apr 29, 2008 #4

    Hans de Vries

    User Avatar
    Science Advisor
    Gold Member

    Indeed :rofl:

    The laws of nature would have to be precise for at least "12 billion" digits behind the
    decimal point. Just to give some arbitrary high number. The way around the free will
    dilemma is the fact that nature can never by infinitely accurate.

    If physical processes in the femtosecond domain are totally deterministic to within
    a precision of 10-17 then your thoughts are predictable for about one minute or
    so after which they start to deviate from the best possible prediction, assuming a
    constant precision loss rate.

    So, the free will dilemma isn't really a point in the determinism debate.

    Regards, Hans.
    Last edited: Apr 29, 2008
  6. Apr 29, 2008 #5

    Ken G

    User Avatar
    Gold Member

    My take is that the mistake is thinking there are only two possibilities: deterministic but unpredictable, or fundamentally random. Both of those are models, I doubt reality is either.
  7. Apr 30, 2008 #6
    I think that it is a possibility too, Ken. It also consistent with the inner experience which we call "free will", which we cannot quite put into words yet seems in contradiction to both strong determinism and randomness.

    But if there is a possibility other than determinism or randomness, I can't grasp what it might be like. It could be that such a thing is incomprehensible to human brains. We should keep trying of course but I am not optimistic.
  8. Apr 30, 2008 #7

    Ken G

    User Avatar
    Gold Member

    Yes, that's one motivation for thinking "outside the box" of the determinism/random dichotomy. The other reason is simply that we should not impose our limited intelligence or reality, but rather seek descriptions of the latter using the former.
    It isn't incomprehensible to our brains, because we've conjured the concepts of "free will" and "God" and if you put those together you have another possibility to deterministic or random. It's not scientifically useful, but it's an example of an alternative. What we want is something that works with science, and that might be the rub. But we never really know what is comprehensible to our minds until a genius finds an angle that makes it understandable.
    Hope springs eternal!
  9. Apr 30, 2008 #8


    User Avatar
    Science Advisor

    Something to note: in the Brain science, neurophysiology world, free will is an increasingly troubled concept. Not because of any problems with determinism or randomness, but rather because of the role of the unconscious. For example; I hate cooked turnips, but rather enjoy raw turnips --not a free choice. some folks completely lose it when cut off on the freeway -- for some, the limbic system takes over, which could lead to flipping the bird, to out-of-control road rage. Some, on the other hand, with mature impulse control, might simply mutter, "That's life..."; which could be consistent with free will, whereas road rage is not governed by free will. (I can dig up some references upon request, some of which deal with experiments.)

    So free will is a serious candidate for mythological status, simply because it is no longer the exclusive property of philosophy, and is being subjected to the standard methods of scientific inquiry. "Take a look and see what happens."

    Randomness? What immediately comes to mind is the classic book, A Random Walk Down Wall-Street, which by means of various statistical tests suggested that the
    Dow Jones index is a random variable. When doing surveys or quality control or sales forecasting, or looking for rare events, randomness as always an issue. Is a random sample really random? Are there biases in quality control testing? The approach in practical circumstances is to rely on commonly accepted statistical tests -- in a sense,
    this defines randomness in operational terms.

    Remember, David Hume destroyed the idea of causality quite a long time ago, so, strictly speaking, the idea of determinism has been dead for several hundred years; apparently few went to the funeral. (His basic notion was;how in the world could you prove A caused B? He concluded, quite reasonably, that such a proof simply does not exist. So, to the extent that randomness means no cause -- like a regression R-squared of 0, with all possible independent variables --, randomness cannot be proved either.

    So, yes randomness is indeed a myth, but ever so valuable a myth. Ditto for determinism, objective reality, and ....
    Reilly Atkinson
  10. Apr 30, 2008 #9

    I don't grant this much significance yet, reilly. I can't say whether these observations made in brain science are incompatible with free will or not because I don't know what free will is. I can only think of the vaguest of definitions.

    I can grant that dislike of cooked turnips may not be a free choice. No taste is, whether it is a taste for Beethoven or a taste for torturing young boys. But what about the choice to act or refrain from acting on that taste? Christians, Muslims, etc. would say therein is the free choice.

    But what is a free choice? I can't isolate it to say for certain whether anything is a "free choice" or not.

    I find it interesting that such a fundamental questions of physics could be at all related to a fundamental question of morality and/or religion.
  11. Apr 30, 2008 #10

    Ken G

    User Avatar
    Gold Member

    Bingo. I think another way to frame that is to ask, what is the difference between a myth and a model? Less than we might like to imagine, but there are differences that have to do with reproducibility and predictability. When an idea does nothing but unify, like MWI say, it is much more like myth than model. For example, if we say "Zeus is an angry god", then we can attribute everything violent and angry-seeming to "the will of Zeus". That is a vastly unifying concept-- we have unified in one fell swoop a vast array of "angry" phenomena-- "Zeus did it". But even so far-reaching a unification can be scientifically sterile when it does not predict and cannot be falsified. So a model is a testable myth, even though it is as unprovable as all myths.
    Last edited: Apr 30, 2008
  12. Apr 30, 2008 #11


    User Avatar
    Science Advisor

    I'll dig up some references; there's a fairly large literature on the subject. Consciousness is being studied similarly. Definitions evolve as knowledge grows. In market research -- practical economics -- and neurophysiology, the point is to study behavior, and attempt to develop connections to brain states.That is, it's all about empirical evidence, something that has been applied to mental stuff for less than a century. Just as religion, at least in the West, had to change its world view during the Renaissance, science will drive society, in general, to new ways of thinking. My sense is that the idea of free will will eventually be thought of as a very simplified approach to aspects of human behavior. The need for that idea will diminish.

    Note the changing attitudes toward mental illness and addiction, both of which I'm familiar with. We don't burn witches anymore; we don't view mental illness as a devilish intrusion. There is no such thing as free will, by any definition, for someone who is severely clinically depressed, or manic, or hearing voices or seeing things that are not there ...

    So, not to worry, the lack of a good definition of free will is one of the reasons the concept is fading away -- at least in the brain science community.
  13. Apr 30, 2008 #12
    If they are merely saying, "'free will' is not a proper subject for study within our science," and that within the bounds of their field it is an empty concept, I could grant them that. But if they go further and say it is an illusion or whatnot, I say they don't know what they 're talking about.

    I highly recommend this little essay btw http://www.pseudobook.com/cslewis/wp-content/uploads/2006/09/meditation.pdf [Broken]
    Last edited by a moderator: May 3, 2017
  14. Apr 30, 2008 #13
    I am not sure that what i am about to post has much relevance but here goes.

    I do not believe in free will or determinism. the way i see it, every single entity exists essentially in its "own" universe inside our universe. everything that you do has a reason, but that reason is only clear to you. from an outside view point that reason maybe seen as random or attributed to "free will" which is the same thing. the other thought that has been floating around my head is that what we term "free will" may be nothing more then the way the small electro magnetic field created by the brain interacts with the atomic and sub-atomic particles that make up our neurons at any given point in space-time. essentially there is a reason and no reason for everything that happens, and both are true at the same time.
  15. Apr 30, 2008 #14
    .. and the energy levels of the harmonic oscillator are [tex]\hbar \omega(n+\frac{1}{2})[/tex].

    Look! quantum physics!

    Mods, please don't move my thread.
  16. Apr 30, 2008 #15
    Why can't it? If there is some elemen of randomness in nature, be it at the 12 billionth digit or at the 34th digit (i.e. h) then we are back to randomness, and away from determinism. Determinisim and random are opposites.
  17. Apr 30, 2008 #16

    Ken G

    User Avatar
    Gold Member

    It sounds like you are arguing it can be infinitely accurate, on the grounds that randomness seems unpalatable. I would point out that these two do not exhaust the possibilities, so failure to be infinitely precise does not imply fundamental randomness, and unpalatability of randomness does not require palatability of infinite precision. It all just means that all our concepts eventually break down, and I think we should not be surprised by that.
  18. May 1, 2008 #17
    I feel I must briefly interject. Your implication in your creationist analogy is inaccurate. Evolution is inane and blatantly absurd. I'm a Christian, but it would take much more faith for me to believe in evolution than it would for me to believe that God created the universe and set in place all the physical laws, mathematics, and so forth. In fact, determining how the universe was created is completely outside the realm of science. Any such scientific claim for or against metaphysical assertions is inherently invalidated. Science is the study of how the universe works and the laws that govern them. Period.
    Last edited: May 1, 2008
  19. May 1, 2008 #18
    No, no, I'm not necessarily saying that randomness is problematic fundamentally. I just believe that conceptually random or deterministic are mutually exclusive possibilities. If one chooses deterministic, then nature is accurate to infinite precision. Anything short of infinite precision introduces randomness into the results, and we are back to traditional QM, just at a deeper level than 10^-34.
  20. May 1, 2008 #19
    Let me also add that randomness is not the same as imprecise. For example, if you try to calculate 1/3 on a 8-digit decimal computer, you will obviously get .33333333 every single time you run the program. However, if you try to calculate 2/3, you will get .66666667 each time. Extend that out a billion decimal places, and the results will still be the same _every time_. If there truly were randomness involved at the smallest levels, sometimes when you caluclate 2/3 you might get .666....667, and sometimes you might get .666.....666, and sometimes even .666.....665, etc. But you don't - you always get the same result every time, even though it's imprecise.

    That's not randomness. That's still deterministic. It's just deterministic but imprecise. If nature is deterministic, then the randomness we see is due to our inability to observe more precise measurements. If nature is fundamentally random, then we will never be able to observre more precisely than roughly 10^-34.
  21. May 1, 2008 #20

    Ken G

    User Avatar
    Gold Member

    I believe that's pretty much what I said, I'm not sure where you imagine a contradiction. Personal beliefs are irrelevant to science, as science makes certain assumptions about the path to objectivity, involving experiment and demonstrability. Your beliefs about how the universe was created are not necessarily wrong, but they are scientifically sterile. And by the way, neither evolution, nor the Big Bang for that matter, are theories about the creation of the universe.
    Last edited: May 1, 2008
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook